|  |  | Summary
Now that you have completed this chapter, you should have a firm understanding of the following: By using layers, the OSI reference model simplifies the task required for two computers to communicate. Each layer's protocol exchanges information, called PDUs, between peer layers. Each layer depends on the service function of the OSI reference model layer below it. The lower layer uses encapsulation to put the PDU from the upper layer into its data field; then, it can add whatever headers and trailers the layer will use to perform its function. The term Ethernet is often used to refer to all CSMA/CD LANs that generally conform to Ethernet specifications, including IEEE 802.3. The Ethernet and 802.3 data links provide data transport across the physical link that joins two devices. IP provides connectionless, best-effort delivery routing of datagrams. It is not concerned with the content of the datagrams, but it looks for a way to move the datagrams to their destination. ICMP messages are carried in IP datagrams and are used to send error and control messages. ARP is used to map a known IP address to a MAC sublayer address to allow communication on a multiaccess medium, such as Ethernet. The switching function allows a router to accept a packet on one interface and forward it on a second interface. Routed protocols are network protocols that provide enough information in the network layer address to allow a packet to be forwarded from host to host based on the addressing scheme. Routing protocol supports routed protocols by providing mechanisms for sharing routing information. Routing protocol messages move between the routers. Most routing protocols can be classified into one of two basic protocols: distance-vector or link-state. Routers must be capable of seamlessly handling packets encapsulated into different lower-level frames without changing the packets' Layer 3 addressing. Examples of IP routing protocols include RIP, IGRP, OSPF, and EIGRP. Transport-layer services allow users to request reliable data transport between hosts and destinations.
| Threaded Case Study
Washington School District Project Task: Getting Started

Throughout this curriculum, you will be applying what you learn to the Washington School District Project. The fictional Washington School District is located in Phoenix, Arizona. Because you will revisit this project within every chapter (it is threaded through the chapters) for the rest of semesters three and four, it is called the "Threaded Case Study" or TCS. The school district is in the process of designing and implementing an enterprise-wide network, which will include LANs at each site and a wide-area network (WAN) to provide data connectivity between all school sites.

Goal: To Create A Dynamic And Relevant Web-based Threaded Case Study.

Objective: To apply your networking knowledge to a real-life example and to help you review concepts integral to the CCNA Certification Exam.

Target: A fictional Elementary School District in Phoenix, Arizona.

Outcomes: Individual work, as well as a Team project. You will document the TCS elementary school district LAN and WAN designs by creating a Web-Based Portfolio. In order to do this, you will need to learn some basic HTML skills.

Tools and Resources:

- Semester 3, v2.1 curriculum
- Semester 4, v2.1 Curriculum
- TCS Overview Document
- School Site Drawings
- Cisco Networking Academy Program: Second Year Companion Guide
- http://students.netacad.net web site
- Browser such as Internet Explorer or Netscape Communicator
- Word or other word processor
- Excel or other spreadsheet
- Notepad or Simple Text or any HTML-editing capable software
- Netscape Composer (or other WYSIWYG editors such as Frontpage or Dreamweaver)
- Bit-mapped graphics editors such as Paint or ClarisPaint
- Cisco Network Designer (CND) Software
- Experts in Networking, including your Instructor
- Industry URLs, such as: http://www.cisco.com, http://www.siemon.com, http://www.fluke.com

After this chapter, you will start the process of completing your Threaded Case Study (TCS) Web-based Portfolio. You need to complete the following tasks:

1. Familiarize yourself with the tools and resources listed above. They will be crucial to your completing the TCS.
2. Master the ability to create simple web sites using the tools indicated by your Instructor.
3. Apply the CCNA Certification Exam Learning Objectives to your specific design. This will require a paragraph on how the learning objectives relate to your design. Learning objectives can be grouped together for the purpose of explanation. In this way, you will be studying for their CCNA Certification Exam as you work through the case study.

CCNA Certification Exam Learning Objectives (*** are explicit CCNA Exam objectives; unmarked are knowledge assumed by the exam):

OSI model

- Identify and describe the functions of each of the seven layers of the OSI reference model.***
- Define and explain the 5 conversion steps of data encapsulation.***
- Identify at least 3 reasons why the industry uses a layered model.***

Addressing

- Define and describe the function of a MAC address.***
- Describe data link addresses and network addresses, and identify the key differences between them.***
- Describe and create the different classes of IP addresses [and subnetting].***
- Identify the functions of the TCP/IP Transport Layer Protocols.***
- Identify the functions of the TCP/IP network layer protocols.***

IOS

- Log into a router using both user and priviledged modes.***
- Use the context-sensitive help facility.***
- Use the command history and editing features.***
- Examine router elements (RAM, ROM, CDP, show).***
- Manage configuration files from the priviledged exec mode.***
- Control router passwords, identification, and banner.***
- Identify the main Cisco IOS commands for router startup.***
- Enter an initial configuration using the setup command.***
- Copy and manipulate configuration files.***
- List the commands to load Cisco IOS software from: flash memory, a TFTP server, or ROM.***
- Prepare to backup, upgrade, and load a backup Cisco IOS software image.***
- Prepare the initial configuration of your router and enable IP.***
- Add the RIP routing protocol to your configuration.***
- Configure IP Addresses.***
- Verify IP Addresses.***
- Explain the services of separate and integrated multiprotocol routing.***
- List problems that each routing type encounters when dealing with topology changes and describe techniques to reduce the number of these problems.***

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